WO2021132585A1

WO2021132585A1 - Black light shielding member

Info

Publication number: WO2021132585A1
Application number: PCT/JP2020/048790
Authority: WO
Inventors: ひのき坂村; 坂爪　直樹
Original assignee: ソマール株式会社
Priority date: 2019-12-27
Filing date: 2020-12-25
Publication date: 2021-07-01
Also published as: JP7157042B2; TWI809340B; CN114846365A; TW202138847A; KR20220118401A; JP2021107896A; KR102570913B1

Abstract

The present invention provides a black light shielding member which has high blackness, while having an antireflection effect due to excellently low gloss.　The present invention produces a black light shielding member which is provided with: a base material film; a resin light shielding layer that is formed on at least one surface of the base material film, while having a relief pattern; and a blackening layer that is formed on the resin light shielding layer. A degree of blackness having an L value of 12 or less is achieved by adjusting so that the arithmetic mean roughness Ra of the surface, on which the light shielding layer and the blackening layer are formed, is not less than 0.25 μm and the maximum thickness of the blackening layer is less than the above-mentioned Ra value.

Description

Black shading member

The present invention relates to a black shading member, and more particularly to a black shading member that can be suitably used for optical devices such as camera units of mobile phones including smartphones.

Usually, a light-shielding member is used for the lens diaphragm, shutter and lens spacer of a camera.
As such a light-shielding member, a black film having a predetermined uneven shape formed on the surface of a black polyester base material containing carbon black or the like is known. Examples of the method for forming the unevenness include a method of coating the surface of the base material with a light-shielding layer containing a matting agent and a method of roughening the surface of the base material by a method such as sandblasting.

In Patent Document 1, the above method or the like is used, and the arithmetic mean roughness Ra of the surface in JIS B0601: 2001 is 0.5 μm or more, and the difference between the maximum peak height Rp and the maximum valley depth Rv (Rp-Rv). ) Is less than 3, it is described that a light-shielding member can be produced. The light-shielding member of Patent Document 1 has excellent antireflection performance even if it is made thinner, has high hardness, and has excellent adhesion between the light-shielding layer and the film base material, so that excellent antireflection performance can be maintained for a long period of time. It is shown.

International Publication WO2018 / 052044 Gazette

In recent years, for the purpose of improving design, there has been a demand for a light-shielding member for an optical device that emphasizes the blackness. However, we have not yet obtained a satisfactory one.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light-shielding member having an antireflection effect due to excellent low glossiness and high blackness.

As a result of diligent research in view of the above problems, the present inventors have made the above-mentioned unevenness in the base film and the black light-shielding member having a resin-made light-shielding layer having an uneven shape formed on at least one surface of the base film. We have found that the above problems can be solved by forming a blackening layer on the shape and further controlling the uneven shape of the surface of the light-shielding member, and have arrived at the present invention. That is, the black light-shielding member of the present invention includes a base film, a resin light-shielding layer having an uneven shape formed on at least one surface of the base film, and a black color formed on the resin light-shielding layer. A black light-shielding member provided with a blackened layer, wherein the arithmetic mean roughness Ra of the surface on which the light-shielding layer and the blackened layer are formed is 0.25 μm or more and the L value is 12 or less, and the blackening is performed. The maximum thickness of the layer is smaller than that of Ra.
Here, the resin light-shielding layer means that at least the uneven portion of the surface forming the blackening layer is made of resin. For example, as will be described later, the resin light-shielding layer of the present invention also includes a structure in which a light-shielding layer containing a matting agent and / or a light-shielding layer not containing a matting agent is formed on the surface of a metal base film having an uneven shape. ..
The arithmetic mean roughness Ra referred to in the present invention is calculated based on JIS B0601: 2001, and the L value is the brightness of ^{the L *} a ^* b ^{* color space calculated based on JIS Z8781-4.} It is an L ^* value that represents.

The resin light-shielding layer preferably has a resin layer containing a matting agent and a resin component.
Further, the resin light-shielding layer may include a roughened portion formed on the surface of the base film.
On the other hand, the blackening layer preferably contains an inorganic material.
The blackening layer preferably contains at least one selected from magnesium fluoride, calcium fluoride, lithium fluoride, aluminum oxide, gallium oxide, and silicon oxide.
Further, the blackening layer is preferably formed by any method selected from a sputtering method, a vapor deposition method, an ion plating method, and a chemical vapor deposition (CVD) method.
Further, the maximum thickness of the blackening layer is preferably smaller than the value of 1/2 of the arithmetic mean roughness Ra of the surface.

The black light-shielding member of the present invention not only has an antireflection effect due to its excellent low glossiness, but also has a high blackness and outstanding blackness, so that it is also excellent in design. Therefore, it can be suitably used as a camera unit of a mobile phone such as a smartphone.

It is sectional drawing which shows the structure of the light-shielding member in one Embodiment of this invention (before blackening layer formation (a), after blackening layer formation (b)). It is sectional drawing which shows the structure of the light-shielding member in another embodiment of this invention (before blackening layer formation (a), after blackening layer formation (b)).

Hereinafter, embodiments of the present invention will be described in detail.
In addition, in this specification, "~" which represents a numerical value range represents the range including the numerical value described as the upper limit value and the lower limit value, respectively. Further, when the unit is described only for the upper limit value in the numerical range, it means that the lower limit value is also the same unit as the upper limit value.
In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise.
Further, in the numerical range described in the present specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
In the present specification, the content or content of each component in the composition refers to the content of each component in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. Means the total content or content of a substance.

Hereinafter, embodiments of the present invention will be described in detail.
The black light-shielding member of the present invention includes a base film, a resin light-shielding layer having an uneven shape formed on at least one surface of the base film, and a blackening layer formed on the resin light-shielding layer. It is a black shading member equipped with
The arithmetic average roughness Ra of the surface on which the light-shielding layer and the blackening layer are formed is 0.25 μm or more, and the blackness (L value) is 12 or less, and the maximum thickness of the blackening layer is It is characterized in that it is smaller than the above Ra.

First, the uneven shape of the resin light-shielding layer of the present invention will be described with reference to the drawings.
Examples of the method for forming the uneven shape of the resin light-shielding layer include the following methods (A), (B) and (C).
In the method (A), as shown in FIG. 1 (a), the surface of the flat base film 2 is coated with the light-shielding layer 3 containing the matting agent 31 and the matrix portion 32. The surface of the light-shielding layer 3 is formed with irregularities by the matting agent 31. Here, Ra on the surface of the light-shielding member 1 can be controlled by adjusting the particle size, particle size distribution, content, film thickness of the light-shielding layer 3 and the like of the matting agent 31. Further, it can be controlled by adjusting the type of solvent, the solid content concentration, and the coating amount on the base film at the time of preparing the coating liquid. Further, it can be controlled by the coating film production conditions such as the coating method of the coating liquid, the drying temperature, the time, and the air volume at the time of drying.

In the method (B), as shown in FIG. 2A, unevenness is formed on the surface of the base film 2. When the base film is a resin film, for example, a sandblasting method can be applied to form irregularities. Here, Ra can be controlled by controlling the particle size, injection pressure, and the like of the abrasive used. Further, for example, a base film containing a matting agent can be produced by adding a matting agent to the raw material of the base film. As the matting agent, the same type as the light-shielding layer described later can be preferably used. Ra on the surface of the base film can be controlled by controlling the particle size, particle size distribution, content and thickness of the base film of the matting agent.
Further, it is also possible to coat the base film 2 on which the unevenness is formed with a coating liquid or the like to form a resin thin film 4 having the uneven shape of the surface of the base film 2 on the surface of the light-shielding member 1. Here, the resin thin film 4 on the surface of the light-shielding member is made of, for example, a resin component such as an acrylic resin, a polyester resin, an epoxy resin, a urethane resin, a urea-based resin, a melamine resin, a fluororesin, or an imide resin. The resin thin film 4 does not contain a matting agent, and Ra and the like on the surface of the light-shielding member 1 can be prepared by the uneven shape of the resin base film 2 and the film thickness of the resin thin film 4.
The material and film thickness of the resin thin film 4 and the blackening layer described later are different. That is, the resin thin film 4 is formed from the resin component, and the film thickness is about 1 to 50 μm, preferably about 2 to 10 μm. On the other hand, the blackening layer described later is formed of an inorganic material, resin particles on the order of submicrons, a binder resin component, or the like, and has a film thickness of about 10 nm to 200 nm.
Due to the above difference, in the black shading member of the present invention in which the blackening layer is formed, a blackness having an L value of 12 or less is realized.

In the method (C), irregularities are formed on the surface of the base film as in (B), and a light-shielding layer containing a matting agent is coated on the surface of the light-shielding member as in (A). In this configuration, Ra on the surface of the light-shielding member depends on the uneven shape of the surface of the base film 2, the film thickness of the light-shielding layer, the particle size of the matting agent in the light-shielding layer, the particle size distribution, the content, the manufacturing conditions of the light-shielding layer, and the like. Can be controlled.

The black light-shielding member of the present invention preferably has a structure in which a light-shielding layer is formed on at least one surface of the base film. In the following description, the uneven shape (roughened portion) formed on the surface of the base film and the resin thin film that does not contain the matting agent that covers the surface, which is formed by the method (B), is also a light-shielding layer. Will be included in.
The specific material composition of the black light-shielding member of the present invention will be described below.

(1) Base film The base film used in the present invention is not particularly limited and may be transparent or opaque. Further, the base film of the present invention may be made of resin or metal.
Examples of the resin base film include polyethylene, polypropylene, ethylene-propylene copolymer, polyolefin such as a copolymer of ethylene and α-olefin having 4 or more carbon atoms, polyester such as polyethylene terephthalate, and polyamide such as nylon. , Other general-purpose plastic films such as ethylene-vinyl acetate copolymer, polyvinyl chloride and polyvinyl acetate, and engineering plastic films such as polycarbonate and polyimide.
Examples of the metal base film include metal sheets using metals such as gold, silver, copper, aluminum, titanium, zinc, beryllium, nickel, and tin, phosphorus bronze, copper nickel, copper beryllium, stainless steel, and brass. An alloy sheet using an alloy such as duralmin can be mentioned.
Among these materials, from the viewpoint of relatively high strength, economy and versatility, biaxially stretched polyethylene terephthalate, from the viewpoint of having heat resistance, polyimide film, from the viewpoint of having even higher heat resistance. Therefore, it is preferable to use a metal sheet made of copper. In the case of a resin base film, a black colorant such as carbon black or aniline black is kneaded in advance to obtain a high light-shielding property with an optical density of 2 or more, preferably 4 or more, thereby achieving a better light-shielding effect. Obtainable.
The thickness of the base film is not particularly limited, but when a resin base film is used, it is preferably 4 to 250 μm, more preferably 12 to 100 μm. By setting the thickness within the above range, it can be suitably used for small and thin optical components. Further, when it is used for an optical device such as a camera unit such as a mobile phone, it is preferably 4 to 20 μm.
When a metal base film is used, the thickness is preferably 6 to 40 μm, and particularly preferably 10 to 20 μm when used in an optical device such as a camera unit such as a mobile phone.

When the above methods (B) and (C) are used, the surface of the base film is matted to form irregularities (roughened portions). The mat processing method is not particularly limited, and a known method can be used. For example, when the base film is a resin base film, a chemical etching method, a blast method, an embossing method, a calender method, a corona discharge method, a plasma discharge method, a chemical mat method using a resin and a roughening forming agent, etc. Can be used. Further, it is also possible to directly contain the matting agent in the base film to form irregularities on the surface of the resin base film. Among the above processing methods, it is preferable to use the blasting method, particularly the sandblasting method, from the viewpoint of ease of shape control, economy, and handleability.
In the sandblasting method, Ra and the like on the surface can be controlled by the particle size and injection pressure of the abrasive used. Further, in the embossing method, Ra and the like on the surface can be controlled by adjusting the embossing roll shape and pressure.
On the other hand, when the base film is a metal base film, irregularities can be formed on the surface by a blackening treatment, a blast treatment, an etching treatment, or the like. When the base film is a metal base film, at least one of a light-shielding layer containing a matting agent and a light-shielding layer not containing a matting agent, which will be described later, is formed on the uneven surface (roughened portion). There is a need.

(2) Anchor layer An anchor layer may be provided in order to improve the adhesiveness between the base film and the light-shielding layer before providing the light-shielding layer on at least one surface of the base film. As the anchor layer, a urea-based resin layer, a melamine-based resin layer, a urethane-based resin layer, a polyester-based resin, or the like can be applied. For example, the urethane resin layer can be obtained by applying a solution containing polyisocyanate and an active hydrogen-containing compound such as diamine or diol to the surface of the base film and curing it. Further, in the case of a urea-based resin or a melamine-based resin, it is obtained by applying a solution containing the water-soluble urea-based resin or the water-soluble melamine-based resin to the surface of the base material and curing it. The polyester resin can be obtained by applying a solution dissolved or diluted with an organic solvent (methyl ethyl ketone, toluene, etc.) to the surface of the base material and drying it.

(3) Light-shielding layer As described above, except for the light-shielding member having only the uneven portion formed on the surface of the resin base film as the light-shielding layer by the method (B), a light-shielding layer is formed on at least one surface of the base film. Cover. The light-shielding layer includes a light-shielding layer containing the matting agent used in the methods (A) and (C) and a light-shielding layer (high hardness layer, thin film) having no matting agent used in the method (B).

The configuration of each light-shielding layer will be described below.
i) Light-shielding layer containing a matting agent The constituent components of the light-shielding layer include a resin component, a matting agent, and a coloring / conductive agent.
The resin component serves as a binder for the matting agent and the coloring / conductive agent. The material of the resin component is not particularly limited, and either a thermoplastic resin or a thermosetting resin can be used. Specific thermosetting resins include acrylic resins, urethane resins, phenol resins, melamine resins, urea resins, diallyl phthalate resins, unsaturated polyester resins, epoxy resins, alkyd resins and the like. Can be mentioned. Examples of the thermoplastic resin include a polyacrylic ester resin, a polyvinyl chloride resin, a butyral resin, and a styrene-butadiene copolymer resin. From the viewpoint of heat resistance, moisture resistance, solvent resistance and surface hardness, it is preferable to use a thermosetting resin. As the thermosetting resin, an acrylic resin is particularly preferable in consideration of flexibility and toughness of the coating film.

By adding a curing agent as a constituent component of the light-shielding layer, cross-linking of the resin component can be promoted. As the curing agent, a urea compound having a functional group, a melamine compound, an isocyanate compound, an epoxy compound, an aziridine compound, an oxazoline compound and the like can be used. Among these, isocyanate compounds are particularly preferable. The mixing ratio of the curing agent is preferably 10 to 50% by mass with respect to 100% by mass of the resin component. By adding a curing agent in the above range, a light-shielding layer having a more suitable hardness can be obtained, Ra of the light-shielding layer can be maintained for a long period of time even when sliding with other members, and an excellent antireflection effect can be obtained. Sustained.

When a curing agent is used, a reaction catalyst can also be used in combination to promote the reaction. Examples of the reaction catalyst include ammonia and ammonium chloride. The compounding ratio of the reaction catalyst is preferably in the range of 0.1 to 10% by mass with respect to 100% by mass of the curing agent.

As the matting agent, resin-based particles or inorganic particles can be used. Examples of the resin-based particles include melamine resin, benzoguanamine resin, benzoguanamine / melamine / formalin condensate, acrylic resin, urethane resin, styrene resin, fluororesin, silicone resin and the like. On the other hand, examples of the inorganic particles include silica, alumina, calcium carbonate, barium sulfate, titanium oxide and the like. These can be used alone or in combination of two or more.
The average particle size, particle size distribution, and content of the matting agent vary depending on the film thickness of the light-shielding layer to be set and the degree of unevenness on the surface of the base film. Adjust to obtain. In the case of the method (A), for example, when a light-shielding layer having a film thickness of 2 to 35 μm is formed on a base film having a smooth surface, the average particle size of the matting agent is usually preferably 1 to 40 μm. When the film thickness of the light-shielding layer is 4 to 25 μm, the average particle size of the matting agent is preferably 5 to 20 μm.

In the case of the method (C), for example, when a light-shielding layer having a film thickness of 1 to 35 μm is formed on a base film having an uneven shape, the average particle size of the matting agent is preferably 2 to 15 μm. When the film thickness of the light-shielding layer is 2 to 7 μm, the average particle size of the matting agent is preferably 2 to 10 μm.
The particle size distribution of the matting agent varies depending on the combination of the film thickness of the light-shielding layer and the size of the selected matting agent, and although it cannot be said unconditionally, it is preferably as sharp as possible. Further, Ra and the like can be adjusted by using a plurality of matting agents having different average particle sizes and particle size distributions.
The amount of the matting agent added depends on the average particle size of the matting agent, the particle size distribution, and the film thickness of the light-shielding layer, but in the case of the method (A), the entire light-shielding layer is taken as 100% by mass, and 20% by mass to 80% by mass. It is preferably%. Further, in the case of the method (C), it is preferably 1% by mass to 40% by mass.
By controlling the surface shape of the resin base film, the average particle size, particle size distribution and content of the matting agent, the film thickness of the light-shielding layer, etc., and adjusting Ra, etc. on the surface of the light-shielding layer, the film can be made thin. Also exhibits excellent light-shielding characteristics.

The shape of the matting agent is not particularly limited, but it is preferable to use a spherical matting agent in consideration of the flow characteristics and coating properties of the coating liquid, the sliding characteristics of the obtained light-shielding layer, and the like. Further, in order to suppress the reflection of light, the matte agent can be colored black with an organic or inorganic colorant. Specific examples of the colorant include carbon black, aniline black, carbon nanotubes and the like. By using a matting agent colored with carbon black and further adding carbon black or the like as a coloring / conductive agent to the light-shielding layer, more excellent light-shielding characteristics can be obtained.

As the coloring / conductive agent, carbon black or the like is usually used. By adding a coloring / conductive agent, the light-shielding layer is colored, so that the antireflection effect is improved and a good antistatic effect can be obtained.
The average particle size of the coloring / conductive agent is preferably 1 nm to 1000 nm, and more preferably 5 nm to 500 nm. By setting the particle size of the coloring / conductive agent within the above range, more excellent light-shielding characteristics can be obtained.
The content of the coloring / conductive agent is preferably 9% by mass to 38% by mass, with the entire light-shielding layer as 100% by mass. By setting the content of the coloring / conductive agent in the above range, more excellent light-shielding characteristics can be obtained.

In the present invention, a leveling agent, a thickener, a pH adjuster, a lubricant, a dispersant, a defoaming agent and the like can be further added as constituent components of the light-shielding layer, if necessary.
As the lubricant, in addition to polytetrafluoroethylene (PTFE) particles which are solid lubricants, polyethylene wax, silicone particles and the like can be used.

A uniform coating liquid is prepared by adding the above components to an organic solvent or water and mixing and stirring. As the organic solvent, for example, methyl ethyl ketone, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, butyl acetate, methanol, ethanol, isopropyl alcohol, butanol and the like can be used.
A light-shielding layer is formed by applying the obtained coating liquid directly to the surface of the base film or on an anchor layer formed in advance and drying it. The coating method is not particularly limited, but a roll coater method, a doctor blade method, or the like is used.
The thickness of the light-shielding layer in the present invention is preferably 1 μm to 35 μm. In particular, when a matting agent is contained, in the case of the method (A), the thickness of the light-shielding layer is preferably 2 μm to 30 μm, and more preferably 4 μm to 25 μm. Further, in the case of the method (C), the thickness of the light-shielding layer is preferably 1 μm to 10 μm, and more preferably 2 μm to 7 μm.
By setting the thickness of the light-shielding layer within the above range, a desired antireflection effect and slidability can be obtained. The thickness of the light-shielding layer containing the matting agent is the height from the surface of the film substrate to the matrix portion not protruding by the matting agent of the light-shielding layer. The thickness of the light-shielding layer can be measured based on JIS K7130.

ii) Light-shielding layer containing no matting agent Next, the light-shielding layer containing no matting agent used in the method (B) above will be described. In this configuration, as described above, the light-shielding property of the light-shielding member is controlled by the uneven shape of the base film, so that the light-shielding layer coated on the surface of the base film can maintain the uneven shape of the base film surface. Must be a thin layer. In such a configuration, the light-shielding layer functions as a conductive layer and a sliding layer.
The constituent components of the light-shielding layer include a resin component and a coloring / conductive agent.
As the resin component, the same material as the light-shielding layer containing the matting agent can be used.

As the coloring / conductive agent, the same material as the material used for the light-shielding layer containing the matting agent can be used.

In the light-shielding layer having this structure, a leveling agent, a thickener, a pH adjuster, a dispersant, an antifoaming agent and the like can be further added, if necessary.
The above components are added to water, alcohol or an organic solvent, and the mixture is mixed and stirred to prepare a uniform coating liquid.
A light-shielding layer is formed by applying the obtained coating liquid directly to the surface of a base film having a concavo-convex shape by matting it in advance or by applying it directly through an anchor layer formed in advance and drying it. The coating method is not particularly limited, but a roll coater method, a doctor blade method, or the like is used.
When the matting agent is not contained as in this configuration, the thickness of the light-shielding layer is preferably 1 μm to 15 μm, and preferably 2 μm to 10 μm. By setting the thickness of the light-shielding layer within the above range, it is possible to impart conductivity, slidability, etc. without disturbing the uneven shape of the base film. The thickness of the light-shielding layer containing no matting agent is the thickness of the light-shielding layer itself in which the waviness on the surface of the film substrate is eliminated.

(4) Blackening Layer The black light-shielding member of the present invention is characterized in that a blackening layer is formed on the unevenness of the resin light-shielding layer described in (3).
1 (b) and 2 (b) show a schematic cross-sectional view of the black light-shielding member 10 of the present invention in which the blackening layer 5 is formed. It is considered that the blackening layer 5 of the black light-shielding member 10 of the present invention is thin and has a structure in which fine layers (fine grains) are unevenly present on the resin light-shielding layer 3. Due to the diffused reflection of (black) light generated on the surface of the blackened layer having such a structure, it is presumed that the black light-shielding member of the present invention has an antireflection effect and a blackness due to excellent low gloss.
That is, the present invention is excellent in low by forming a thin blackening layer on a resin light-shielding layer having an uneven shape and adjusting the arithmetic mean roughness Ra of the surface to be 0.25 μm or more. It was completed by finding that the antireflection effect due to the glossiness and the blackness with an L value of 12 or less can be realized. The maximum thickness of the blackening layer is not particularly limited as long as it is smaller than Ra, but is preferably 10 nm to 200 nm, more preferably 50 to 150 nm, and even more preferably 70 to 110 nm.
The maximum thickness of the blackened layer can be calculated from microscopic observation photographs and the like.

The blackening layer may be an inorganic material or an organic material, and may be a mixed material of an organic material and an inorganic material or a composite material as long as the above conditions are satisfied. Examples of inorganic materials include metals such as gold, silver, copper, platinum, cobalt, tin, zinc, lead, palladium, ruthenium, neodium, samarium, aluminum, magnesium, indium, gallium, bismuth and alloys thereof, and oxidation. Aluminum, silicon oxide (silicon dioxide, etc.), titanium oxide (titanium monoxide, titanium pentoxide, titanium dioxide, etc.), indium tin oxide (ITO), cerium oxide, zinc oxide, chromium oxide (Cr ₂ O _3, etc.), oxidation Metal oxides such as gallium, hafnium oxide, nickel oxide, magnesium oxide, niobide oxide (niobium pentoxide, etc.), tantalum oxide (tantal pentoxide, etc.), yttrium oxide, zirconium oxide and their composites, magnesium fluoride, foot Aluminum oxide, calcium fluoride, cerium fluoride, lanthanum fluoride, lithium fluoride, sodium fluoride, neodium fluoride, samarium fluoride, itterbium fluoride, ittium fluoride and other fluorides, titanium nitride, chromium nitride, charcoal Oxides such as titanium nitride, titanium aluminum nitride, boron nitride, aluminum nitride, carbon nitride, carbon nitride, carbon (amorphous carbon, diamond, diamond-like carbon, graphite, etc.), titanium carbide, silicon carbide, boron carbide, tungsten carbide Such as carbides can be mentioned.
Examples of the organic material include submicron particles such as an acrylic resin, a styrene resin, a silicone resin, and a fluororesin. Further, an organic-inorganic hybrid material (organic-inorganic nanocomposite material) in which the above metal oxide and an organic molecule are composited can also be used.

The method for forming the blackened layer is not particularly limited, but is a dry method (dry method) such as a sputtering method, a vacuum vapor deposition method, an ion plating method, a chemical vapor deposition (CVD) method, and a coating method using a sol-gel method. , And a wet method (wet method) such as a coating method in which a sol solution or a dispersion liquid obtained by dispersing and mixing the material of the blackening layer with a solvent and a binder component is applied is used.
Of these, the dry method is preferable because a more excellent blackening effect can be obtained. In the process of forming the blackening layer by the dry method, it is considered that nanometer-level particles adhere to the uneven convex parts, concave parts and inclined surfaces of the light-shielding layer to form a more complicated and uneven uneven shape. Be done. In the light-shielding member having such a surface shape, the incident light is absorbed while being reflected in a complicated manner on the surface of the blackening layer, so that it is presumed that the antireflection effect and the blackness due to the better low glossiness are realized. ..
Further, unlike the wet method, the dry method is also preferable in that the surface roughness does not decrease due to the accumulation of the coating liquid in the recesses. Further, since no solvent is used, there is little adverse effect on the environment, and the equipment is relatively small, which is also preferable.
Among the dry methods, the sputtering method is preferable because it is excellent in adhesion to the light-shielding layer, scratch resistance, and ease of adjusting the thickness.

On the other hand, the wet method is preferably used from the viewpoint of cost effectiveness because it is excellent in economy, workability, yield and the like. In the wet method, the sol solution or dispersion is applied to the convex, concave and inclined surfaces of the light-shielding layer, and during the drying process, convection occurs from bottom to top when the solvent evaporates, resulting in unevenness. It is considered that a more complicated and non-uniform uneven shape is formed on the surface of the light-shielding layer having the above. In the light-shielding member having such a surface shape, the incident light is absorbed while being reflected in a complicated manner on the surface of the blackening layer, so that it is presumed that the antireflection effect and the blackness due to the better low glossiness are realized. ..
The material and forming method of the blackening layer, the thickness of the layer, and the like can be appropriately set in consideration of the characteristics and cost required for the light-shielding member.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "%" and "part" indicate mass% and parts by mass.

<Structure of black shading member>
(1) Base film (1-1) Polyimide film: Capton 50MBC (thickness 12 μm), manufactured by Toray DuPont (1-2) Copper foil film: NC-WS (thickness 12 μm), manufactured by Furukawa Denko Co., Ltd. (1) 1-3) Polyethylene terephthalate film: A film in which both sides of Lumirror X30 (thickness 50 μm, manufactured by Toray Industries, Inc.) are sandblasted to form irregularities on the surface.
(2) Light-shielding layer (a) Resin (a1) Acrylic resin: Acrydic A814, manufactured by DIC Co., Ltd. (b) Hardener (b1) TDI-based polyisocyanate: Coronate L, manufactured by Toso Co., Ltd. (c) Coloring / conductive agent (C1) Carbon black; NX-592 black, manufactured by Dainichi Seika Kogyo Co., Ltd. (d) Matte agent (d1) Acrylic filler: MX-200 (average particle size: 2 μm), manufactured by Soken Kagaku Co., Ltd. (d2) Acrylic filler : MX-300 (average particle size: 3 μm), manufactured by Soken Kagaku Co., Ltd. (d3) Acrylic filler: MX-500 (average particle size: 5 μm), manufactured by Soken Kagaku Co., Ltd.

(3) Blackening layer (3-1) Formation by sputtering method Using a sputtering device (model: CFS-4ES) manufactured by Shibaura Eletech Co., Ltd. _{, targeting magnesium fluoride (MgF 2} ), by sputtering method in argon. A magnesium fluoride layer was formed. Here, the ultimate pressure was 3 × 10 ^-3 Pa, the sputtering pressure was 7.6 × 10 ^-3 Pa, and the Ar flow rate was 11 sccm. A magnesium fluoride layer was formed in advance on a flat substrate under predetermined conditions (200 W), and the relationship between the sputtering time at that time and the thickness of the layer was determined. The magnesium fluoride sputter-forming films formed under the conditions that the layer thicknesses are 80 nm, 100 nm and 120 nm, respectively, are defined as a thin film, a middle film and a thick film, respectively.

(3-2) Formation by application of dispersion liquid (3-2-1) Binder component: Polyester resin Magnesium fluoride particle dispersion (9076MF, primary particle diameter 39 nm, solid content 26%: manufactured by Tokushiki Co., Ltd.) , 2 parts of a resin solution dissolved in methyl ethyl ketone and 87 parts of methyl ethyl ketone were mixed so that the concentration of the polyester resin (Byron 200: manufactured by Toyo Boseki Co., Ltd.) was 10% by mass to prepare a coating liquid. The obtained coating liquid was applied by a bar coating method and dried by heating to form a blackening layer having a thickness of about 100 nm.
(3-2-2) Binder component: 1 part of magnesium fluoride particle dispersion used in silicon dioxide (3-2-1) and silica sol solution (Colcoat N-103X (solid content 2%), manufactured by Corcote). Was diluted to 20% with n-butanol, and 90 parts of propylene glycol monomethyl ether were mixed to prepare a coating liquid. The obtained coating liquid was applied by a bar coating method and dried by heating to form a blackening layer having a thickness of about 100 nm.
(3-3) Formation by sol-gel method 25 parts of silica sol liquid (Colcoat N-103X (solid content 2%), manufactured by Corcote) and 75 parts of a solvent having a mass ratio of water: isopropyl alcohol of 1: 2 are mixed. To prepare a coating solution. The obtained coating liquid was applied by a bar coating method and dried by heating to form a blackening layer having a thickness of about 100 nm.

(Examples 1 to 12, Comparative Examples 1 to 9)
Each component of the above (2) light-shielding layer was put into a solvent at the compounding ratio (mass) shown in Tables 1 to 3 and mixed by stirring to obtain a coating liquid. Here, as a solvent, methyl ethyl ketone and toluene were used.
Using the base film shown in Tables 1 to 3, the coating liquid having the composition of Tables 1 to 3 was applied to one surface, and then dried at 100 ° C. for 2 minutes to form a light-shielding layer.
On the obtained light-shielding layer, the blackening layer shown in Tables 1 to 3 was formed by the method described in (3) above. Tables 1 to 3 show the results of measuring the average film thickness of the light-shielding layer, the average film thickness of the blackening layer, Ra of the light-shielding member, the glossiness with respect to the incident light at an incident angle of 60 °, and the L value. The arithmetic mean roughness Ra of the light-shielding member was calculated based on JIS B0601: 2001, and the L value was calculated based on JIS Z8781-4. Further, the glossiness for the incident light at the incident angle of 60 ° was measured according to JIS Z8741, and the mirror glossiness for the incident angle of 60 ° was measured.
The average film thickness of the light-shielding layer was measured based on JIS K7130. The thickness of the light-shielding layer containing the matting agent was set to the height from the surface of the film substrate to the matrix portion not protruding by the matting agent of the light-shielding layer. On the other hand, the thickness of the light-shielding layer containing no matting agent was the thickness of the light-shielding layer itself in which the waviness on the surface of the film substrate was eliminated.
The average film thickness of the magnesium fluoride blackening layer by the sputtering method described in the table is not an actual measurement value, but is the case where the magnesium fluoride layer is formed on a flat substrate by the sputtering method under the same conditions as when it is formed on the light-shielding layer. Average film thickness. Further, the average film thickness of the blackened layer by the dispersion coating method and the sol-gel method shown in Table 3 is not an actually measured value as in the case of forming the blackened layer by the sputtering method, but under the same conditions as when the blackened layer is formed in the light-shielding layer. It is the average film thickness when each blackening layer is formed on a flat substrate by a dispersion coating method and a sol-gel method.

As shown in Table 1, in Reference Example 1, which is a flat polyimide film, Ra is as low as 0.2 μm, the glossiness at an incident angle of 60 ° is 35.4%, and the L value is 28.3. It was found that both the antireflection effect and the blackness due to the low glossiness were low. On the other hand, in Comparative Example 1 in which the light-shielding layer containing the matting agent was provided, Ra increased to 0.48 μm, the surface was roughened, and the antireflection effect and the blackness due to the low glossiness were improved. However, the blackness was not sufficient.
On the other hand, in Examples 1 to 3 in which a blackening layer which is a sputtering forming film of magnesium fluoride was further provided on the light-shielding layer, both the glossiness and the L value at an incident angle of 60 ° were significantly reduced, which was excellent. It was confirmed that it has an antireflection effect due to its low gloss and a blackness. In particular, the black shading members of Examples 1 and 2 in which the blackening layers of the media and the thin film were formed had a Ra of 0.48 μm or more as compared with the black shading member of Comparative Example 1 having no blackening layer. , 1.28 μm and 1.32 μm, respectively. Further, the Ra of the black light-shielding member of Example 3 in which the blackened layer of the thick film was formed was 0.49 μm, and the rate of increase of Ra was lower than that of Examples 1 and 2. From this, the film thickness of the blackening layer does not become too thick, and by setting it within an appropriate range, the unevenness of the surface of the black light-shielding member becomes more complicated, and antireflection due to excellent low glossiness. It was found that a light-shielding member having an effect and a higher blackness can be obtained.
It was found that in Reference Example 2 in which the blackening layer of the middle film was formed on the flat polyimide film, the glossiness and the L value at the incident angle of 60 ° were almost the same as those in Reference Example 1. From this, the effect of the present invention in which the blackening layer was formed on the surface of the light-shielding layer having an uneven shape was confirmed.

Table 2 shows Ra of the surface of the light-shielding member when a blackening layer of the middle film is formed on the surface of the light-shielding layer whose surface roughness is changed by using matting agents having different particle sizes, at an incident angle of 60 °. The result of comparing the glossiness and the L value is shown. As shown in Comparative Examples 1, 4 and 5, the surface Ra changes by changing the particle size of the matting agent added to the light-shielding layer, but the L value exceeds 20 in all the comparative examples, which is sufficient. It turned out that a good blackness could not be obtained. On the other hand, in Examples 1, 4 and 5 in which the blackened layer of magnesium fluoride in the middle film was formed by the sputtering method, both the glossiness and the L value at the incident angle of 60 ° were significantly reduced, which was excellent. It was confirmed that it has an antireflection effect due to its low glossiness and a high blackness.

In Example 6 of Table 3, the results of evaluating the sample having the light-shielding layer and the blackening layer formed in the same manner as in Example 1 except that the copper foil film was used as the base film are shown. In Example 6, Ra increased and both the glossiness and the L value at an incident angle of 60 ° decreased significantly as compared with Comparative Example 6 in which the blackening layer was not formed. From this, it was confirmed that the effect of the present invention can be obtained even if a metal base film is used as the base film.

Further, in Example 7 in which a polyethylene terephthalate film was used as a base film and a blackening layer was directly formed on the blasted surface, a blackening layer was formed after forming a light-shielding layer containing a matting agent on the blasted surface. The same evaluation was performed for Example 8 and Example 9 in which a blackening layer was formed after forming a light-shielding layer containing no matting agent on the blasted surface. Compared to Comparative Examples 7, 8 and 9 in which none of the light-shielding members formed the blackening layer, Ra increased, and the glossiness and L value at an incident angle of 60 ° were significantly reduced. From this, it was found that the effect of the present invention can be obtained regardless of the method of forming the unevenness of the light-shielding layer.

In Example 10, a black light-shielding member was produced and evaluated in the same manner as in Example 1, except that the blackening layer was replaced with a sputtering layer and a magnesium fluoride / polyester resin layer formed by a dispersion coating method was used. In Example 10, as compared with Comparative Example 1, Ra increased, the glossiness at an incident angle of 60 ° decreased, and the L value decreased significantly. From this, it was confirmed that the effect of the present invention can be obtained even with the blackened layer formed by the wet method.
Further, in Example 11, instead of the sputtering layer, a magnesium fluoride / silicon oxide layer was used, and in Example 12, a black light-shielding member was produced in the same manner as in Example 1, except that the silicon oxide layer was used. And evaluated. In both Example 11 and Example 12, Ra increased, the glossiness at an incident angle of 60 ° decreased, and the L value decreased significantly as compared with Comparative Example 1. From this, it was confirmed that the effect of the present invention can be obtained in a configuration in which a thin and non-uniform blackening layer is formed on the resin light-shielding layer regardless of the method and material for forming the blackening layer.

1 Light-shielding member (before forming the blackening layer)
10 Light-shielding member (after forming the blackening layer)
2 Base film 3 Light-shielding layer 31 Matting agent 32 Matrix part 4 Light-shielding layer (resin thin film)
5 Blackening layer

Claims

A black light-shielding member including a base film, a resin light-shielding layer having an uneven shape formed on at least one surface of the base film, and a blackening layer formed on the resin light-shielding layer. ,
The arithmetic mean roughness Ra of the surface on which the light-shielding layer and the blackening layer are formed is 0.25 μm or more and the L value is 12 or less, and the maximum thickness of the blackening layer is smaller than Ra. A black shading member characterized by this.
The black light-shielding member according to claim 1, wherein the resin light-shielding layer has a resin layer containing a matting agent and a resin component.
The black light-shielding member according to claim 1 or 2, wherein the resin light-shielding layer includes a roughened portion formed on the surface of the base film.
The black light-shielding member according to any one of claims 1 to 3, wherein the blackening layer contains an inorganic material.
The black light-shielding member according to claim 4, wherein the blackening layer contains at least one selected from magnesium fluoride, calcium fluoride, lithium fluoride, aluminum oxide, gallium oxide, and silicon oxide.
The black shading layer according to claim 4 or 5, wherein the blackening layer is formed by any method selected from a sputtering method, a vapor deposition method, an ion plating method, and a chemical vapor deposition (CVD) method. Element.
The black shading member according to any one of claims 1 to 6, wherein the maximum thickness of the blackening layer is smaller than a value of 1/2 of the arithmetic mean roughness Ra of the surface.